SEBD0518-09 Fig. 74: Cleaning the tube bundles.
Fig. 73: Battery Ground.
Aftercooler Cores
See Technical Marking Information (TMI) for Marine Application Performance Specifications.
Usually, an aftercooler core used on a vehicle receives adequate air supply. However, adequate air supply is crucial if an aftercooler core is used on an engine that is in a room. If this is the case, make sure all blowby fumes are directed out of the room. If the fumes are piped into the air intake, they will decrease the efficiency of the aftercooler.
The water side of the core can be kept clean by the use of correct maintenance procedures. This is not true with raw water aftercoolers. Sea water and stream water can plug the water side of the core. A
temperature check of the air, after it goes through the aftercooler, will determine whether or not the
aftercooler core is plugged. Ideally, the inlet manifold air temperature will never be above 52°C (125°F), but the temperature on some arrangements can reach 93°C (200°F). If the aftercooler core is clean and the
temperature of the sea water is 29°C (85°F), the air temperature on marine engines must not be more than 49° + 2.8°C (12° ± 5°F). The air temperature will decrease 1° (Fahrenheit or Centigrade) for each 1°
(Fahrenheit or Centigrade) the water temperature is under 29°C (85°F). This means if the temperature of the sea water is 18°C (65°F) and the aftercooler core is clean, the air temperature must be 38° ± 2.8°C
(100° ± 5°F). If the sea water is 18°C (65°F) or lower and the air temperature goes above 52°C (125°F) on marine engines, the aftercooler core needs to be investigated. If the jacket waterside temperature differential is low, suspect an aftercooler problem. If the jacket waterside temperature differential is high, check the pump as pump flow is most likely the problem.
Because of the construction of the aftercooler, it is impossible to clean the inside of the tube bundles with a rod. But it is possible, with special plumbing, to reverse the flow of raw water through the aftercooler to back flush it. This can be accomplished by running the engine for approximately one hour with a light load or no load. This will help clean the core. If this is not possible, remove all the pipes connected to the aftercooler and make adapters that can be used to flush the core with fresh water. If fresh water is used to clean the core, the water pressure must not be more than 170 to 205 kPa (25 to 30 psi). Do not stop the outlet flow of water out of the core and let the water pressure build up in the core. If the aftercooler core can be removed easily, it is best to clean it in a shop.
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Radiator Cap
The radiator cap must prevent water and pressure loss in the cooling system. On large radiator caps, a worn gasket can be replaced. Smaller automotive type radiator caps cannot be serviced. A new cap must be installed.
Relief Valve
The cooling system relief valve cannot be serviced but it can be cleaned. If there is a loss of pressure in the cooling system, install a new relief valve and plate.
Fan Belts
Fan belts come in a set. If one of the fan belts is worn, all the fan belts must be replaced.
Pulleys
Some pulleys can be reconditioned under certain conditions. A pulley is reconditioned by remachining the grooves. For reconditioning procedures and specifications, see Guideline for Reusable Parts, Cast Iron And Steel Pulley Grooves, Form SEBF8046.
Pulleys wear on the side faces of the groove. This wear is caused by abrasive material between belts and grooves. As the pulley wears, the belt will drop deeper into the groove. If the belt and pulley are in good condition, the belt will extend beyond the pulley edge as shown in Figure 75.
Do not use belt dressing or other compounds that prevent belt slippage. Most of these compounds will make the side walls of the belt soft and weak and cause the belt to wear.
Fan Assembly
Do not repair a damaged fan assembly. When a fan is constructed, a balance point is established so the fan will run with a minimum amount of vibration. A repair would affect this balance point and can weaken the structure of the fan.
Fan Shroud and Baffles
The fan shroud and baffles cannot be reconditioned.
Make sure these parts are installed when a radiator core is replaced. The fan shroud and baffles have an effect on fan efficiency and prevent recirculation of air. At times, wear or interference between the fan blade tips and the baffles will be noticed. This is normal. When a radiator guard flexes, it can cause the shroud to contact the tips of the fan blades.
Radiator Mounts
The flexible radiator mounts protect the radiator from damage normally caused by machine and/or engine vibration. When a radiator is removed for any repair, check the mounts, especially the condition of the rubber. If the rubber is deteriorated, install new mounts. Be sure the mounting bolts are tightened to the correct torque. See the appropriate Service Manual module.
Fan Guards
Vibration can damage fan guards. Make sure the bolts that hold the fan guards are tight at all times. If a guard wire is broken at an original weld joint, it can be tack welded into place. If a guard wire is broken, a new wire must be installed.
Water Temperature Regulators
There are no parts in the water temperature regulator that can be repaired. See the topic, "Test Water Temperature Regulators" on page 46.
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Fig. 75:. When fan belts and pulleys are in good condition belts extend beyond the edge of the pulley.
Hoses and clamps
On machines where it is possible, turn the valves in the heater lines to the "OFF" position during summer months so that there is no system pressure in the heater hoses. If one heater hose comes loose, all of the coolant can be lost if coolant flow is available to these hoses. Knowing the location of heater hoses is
important because they must be checked often.
When you install hose clamps, do not tighten them too much. Tighten the clamp until it compresses the rubber coating on the hose. If the clamp tears the rubber coating, revealing the cords in the hose, it has been over tightened. Hoses are usually replaced when they have a leak or during a scheduled service interval.
Remember, all hoses in the cooling system are made of similar material and operate in the same
environment. So, if any one hose starts to leak, replace all of the hoses. If a scheduled service interval is used, change hoses every three years or 4000 hours.
It is difficult to check the condition of a hose because all hose coverings are painted and it is normal for paint to flake, check, and crack. As pressure in a cooling system increases, the hoses expand, causing the paint to check. The exterior appearance of the hose is not a good indication of wear. The "feel" of the hose is a good indication of wear. When the temperature of the cooling system is cold and the pressure in the system is released, the hose will need to be replaced if it feels soft. Softness of the hose may be due to a number of factors. If a radiator or cooling system has had oil in it, the inner liner of the hose will soften. The hose will also feel soft if it is very old and the inner liner has loosened from the fabric. A loose inner liner can fold down into a water passage on the suction side of the water pump and restrict the flow of coolant. An inner liner folded into a water passage is not only rare, but because there is no external leakage, it is also difficult to find. Finding a loose liner is especially difficult if you are troubleshooting an overheating problem.
Temperature Gauges
There are two types of temperature gauges, electrical and mechanical. If there is a problem with an electric gauge, the temperature sending unit and the gauge must be checked separately. With the mechanical gauge, the bulb and tube are fastened to the gauge and must be checked as a unit. If you install a new
mechanical gauge, make sure the tube is long enough
for correct installation.
There are different types of mechanical gauges and their red ranges are different. The red range is 108°C (227°F) for most gauges and 99°C (210°F) for highway trucks. The red range for most transmission temperature gauges is 132°C (270°F). The part number is different on each gauge because of the difference in the length of the tube to the bulb.
Later model machines have EMS panels. On these machines, the high coolant temperature light will come on at a temperature of 107°C (225°F).
Water Pump
The need for water pump repair is generally the result of seal leakage. All water pumps have a drain cavity in the pump housing. The cavity will direct water leakage to the ground. If this cavity is closed, the water will be pushed past the oil seal on the shaft, allowing the water to get into the engine oil system. This will cause damage to the engine.
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Fig. 76: Water pump.
Seal assemblers are available for all water pumps.
Some seal assemblers come with a small tool that is used to install the seal and ring correctly. Clean water, used as a lubricant, will make the installation of the seal easier. Never use oil as a lubricant. Oil can make the seal swell or soften or cause it to turn on the shaft.
The bearings in the water pump can be replaced when the pump is reconditioned. The impeller, shaft, and cover can be used again, unless there was a bearing failure and the pump has operated for some period of time. Most of the time the impeller wears into the cover when there is a bearing failure.
NOTE: When reconditioning a water pump, make sure the shaft is clean before any seals are installed.
Rust or scale can tear the seal. Do not use a hammer to install the impeller. A hammer will crack the seal face.
Use a press or a retaining bolt to pull the seal in position on the shaft.
NOTE: When installing a new water pump, put a small amount of oil on the bearings. Do not start or turn over an engine unless the cooling system is filled with coolant. If the water pump is operated in a dry condition, seal failure will result from overheating.
NOTE: If a cooling system has been flushed, check the condition of the water pump closely for
approximately one week. Many times, a seal failure will result soon after the cooling system has been flushed. This is because the loose rust and scale, which is purged by the cleaning process, goes through the pump seal area.
Cylinder Heads
Normally, cylinder head repair is needed because of leaks or cracks. A defect in a core plug (freeze plug) in the top deck of the cylinder head can cause a leak. If there is a leak in this area, water spots will be visible in the plug recess. The old plug must be removed, the hole for the plug cleaned and a new plug installed.
Make sure to put a sealant on the new plug before installation.
Cracks in a cylinder head are generally found between valve ports. Cracks can also be found at
precombustion chamber or nozzle openings to a valve port. Cracks in a cylinder head can be repaired by a remanufacturing welding process. Remanufactured cylinder heads are available from the Caterpillar Parts Distribution System.
Before installing a new precombustion chamber in a cylinder head, check the precombustion chamber gasket surface in the head for pits or rust. If there are pits or rust, a new precombustion chamber will not seal correctly.
If you remove a precombustion chamber from a cylinder head, install a new O-ring seal on the precombustion chamber before it is used again in the head. O-ring seals can harden and break. If there is a leak in the area around the seal, overheating will result, especially if scale prevents heat transfer from the body of the precombustion chamber. Also, it is important that a new gasket is installed. This gasket helps make sure the hole for the glow plug is in the correct position. See the appropriate Service Manual module for the orientation of this hole.
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Fig. 78: Freeze plug in cylinder head.
Fig. 77: Use a special tool to install the seal assembly.
Cylinder Block
If an engine has been completely disassembled, check the condition of the cylinder block carefully.
Be sure to measure the depth of the counterbores for the cylinder liners. The thickness of the flange on the cylinder liner must be more than the depth of the.
counterbore. See the appropriate Service Manual for the correct liner projection. If the liner projection is not correct, there will be insufficient compression on the cylinder head gasket. If the counterbore has been damaged by a loose cylinder head, a fretting pattern will be visible on the ledge of the counterbore. The block can be reconditioned with a counterboring tool and the use of inserts under the flange of the cylinder liner. These inserts are available from the Caterpillar Parts Distribution System.
If the deck surface of a cylinder block is damaged, consult the factory for information as to how much stock can be removed from the block. If the block is ground, the clearance will decrease between the valves and the top of the pistons at top dead center of
crankshaft rotation for that cylinder.
Cylinder Liners
Check the condition of the cylinder liners. Look for fretting on the flange and any pits and scale on the water side of the liner. If there are pits in the liner, turn the liner 90° from its original position during
reinstallation in the, cylinder block. Put liquid soap on the lower seals of the liner before installation. Do not use ethylene glycol on these seals because some of it may drain down to the oil pan and give a positive antifreeze reaction in an S• 0•S Services oil analysis test. Put mineral oil or crankcase oil on the upper seal in the liner. Install the seal immediately. The mineral oil or crankcase oil will cause the seal to swell.
Normal wear dimensions for the different types of cylinder liners can be found in the Service Manual.
Test Equipment
Troubleshooting and analyzing cooling system
conditions can be easier with the right test equipment.
See pages 62-69 for cooling system troubleshooting and analyzing tools available from the Caterpillar Parts Distribution System.
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Fig. 80: Filler band and O-ring seals on cylinder liner.
Fig. 79: O-ring seals and gasket on precombustion chamber.
Cat ELC (Extended Life Coolant)
Developed, tested, and approved by Caterpillar, Cat ELC lasts up to six times as long as conventional coolant. Cat ELC requires no supplemental coolant additives (SCA's); instead, Cat ELC Extender is added once, at 6000 service hours or one half of the service life. Cat ELC is the coolant used as standard factory fill worldwide for all Caterpillar machines. Cat ELC can be used in all Cat and most OEM diesel and gasoline engines.
See page 18 for available quantities and part numbers.
Supplemental Coolant Additive
Cat SCA helps prevent rust, mineral and deposit formation in the cooling system. Cat SCA helps protect all metals, including aluminum. Cat SCA does not affect gaskets or hoses and is compatible with glycol-base antifreeze.
See page 24 for available quantities and part numbers.
Supplemental Coolant Additive Elements
Spin-on supplemental coolant additive elements contain a pre-measured amount of chemical coolant additives that dissolve during engine operation. The elements can be used year-round to help prevent cavitation, corrosion, and erosion. Elements are available for most Cat diesel engines. To avoid over-concentration, never use supplemental coolant additive elements and liquid supplemental coolant additive simultaneously. Never use supplemental coolant additive elements with Cat ELC.
See page 24 for available quantities and part numbers.
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